About 18 mos ago, I made up some loads for 2 of my rifles.
about a month ago I took my ruger 22-250 out, I switched the scope out and finally got around to shooting it. The loads I had usually shot at least MOA, but for some reason I was getting terrible groups of about 2.5" and larger. I was pretty dissapointed, I didn't think much about it. Then today I took my rem .270 to resite in, again after a scope change, I decided to site the gun in with winchester factory ammo as I was running low on handloads. The 270 did pretty good with the factory ammo with groups around MOA or a little more. Then I switched over to my loads, I had tested them same as above and last year was getting about 3/4 moa average. Today same as the Ruger 3" groups. It finally doned on me there is something wrong with my loads. They have been stored in a platic box, you know the ones for reloads. They have also been in my range box, which I have been leaving in my trucks back seat most of the time. My truck is pretty bouncy, is there a way these factors could be causing problems with my handloads. As usual My little CZ shot rings around both rifles. So does anyone have an idea as to what is going on here??

Being that you changed 'scopes on both rifles, and then your groups became patterns, I would think that the problem is with the new 'scopes.

I doubt it is with your reloads, and I seriously doubt that it is because your are keeping thme in plastic boxes and in the truck.

I use the 50 cartridge MTM cases for all my reloads, and I have been known to forget to remove them from the Bronco on occasion, until a year later...when I find them under the seat. (Always wondered why I heard a strange sound in the Bronco after hunting season...)

i don't think it is scope problem, cause both rifles are shooting the factory stuff OK. It is just when I use my loads a problem arises. I use the same MTM 50 round boxes. I just don't get it.

check your bedding.

Try making up a new test batch of your current reloads & try those. Ammo stored in adverse conditions (heat,cold, constant vibration can settle &/or break up some powders) like you have stated, can cause you some accuracy problems. It shouldn't be as bad as you described, after all, your factory ammo is shooting ok.

Just a thought... check the OAL length of your handloads. If they arent crimped, it would be possible for the bullets to work their way into the case some and change the OAL. Some rifles do not like excessive bullet jump.

One thing to consider; are you careful to remove any lube from the inside of the case neck when you load? Over a period of time, any lube missed can contaminate the powder and make for inconsistant ignition and burn. In the short term, it desn't seem to have the same effect.

cummins,

We find something in the last place we look for it. When we get lucky and find it we think we are all so smart. Sometimes it gets hard to find it.

There are many causes of inaccuracy. While your ammo might be the cause something else might also. Just make up some new ammo and try again.

This is a really good reason to have many rifles